Heater



FIG. 1 is a front elevation view of the heater;

FIG. 2 is a back elevation view of the heater;

FIG. 3 is a right elevation view of the heater;

FIG. 4 is a left elevation view of the heater;

FIG. 5 is a top plan elevation view of the heater;

FIG. 6 is a bottom plan elevation view of the heater; and,

FIG. 7 is a perspective elevation view of the heater. 

The ornamental design for a heater, as shown and described. 